Momentum 4.42 x 10^-24 Ns; energy = 1.33 x 10^-15 J or 3.28 keV
3.50 x 10^-44 kg, or 1.97 x 10^-8 eV/c^2
m takes integer values between -3 and +3; 14 electrons can be accommodated.
N/A
Kappa = 1.15 x 10^10 m^-1 (don't forget the units!); to reduce current by factor of 10, must increase barrier width by ln(10)/(2 kappa) = 1.0 x 10^{-10}m.
Delta x = 5.5 x 10^-12 m. [Note this was using the form of the uncertainty principle Delta x Delta p >= hbar. Other answers are possible if you take other forms of the uncertainty principle, and full marks were awarded for these.]